Delta flyers can stop worrying about taking that big trip before their airline miles expire. Delta announced Tuesday that SkyMiles will no longer expire, effective Jan. 1, 2011.

"We know how much customers value their miles, so eliminating mileage expiration is a major win for them," Jeff Robertson, Delta's vice president - SkyMiles, said in a statement.

The airline says it's the only U.S. carrier whose miles never expire. Previously, miles expired 24 months after a customer last earned or redeemed miles.

I used to travel a lot and used the now defunct U.S. Bank WorldPerks card as my go-to credit card. But as our family grew and we loaded baby gear on top of the suitcases in storage, I switched to cash-back cards. The only time I would use my airline miles was to buy magazine subscriptions days before they were set to expire. I just never earned enough miles in time to book a seat with points.

But even frequent travelers have had trouble in recent years, if my e-mail in-box is an indication. I've heard from frequent travelers who say it's nearly impossible to redeem award seats with Delta, especially in the award travel tier that requires the lowest number of miles.

Others have complained to the newspaper about problems with seat upgrades. Suzanne Ziegler wrote about Michael Kaldenberg's upgrade woes last year. The sales VP travels as much as 200,000 miles a year and still found himself in coach.

Delta has announced several improvements to its program over the past year so, including the elimination of all award redemption fees and a free checked bag for most Delta SkyMiles American Express users. The airline says its award travel calendar and booking process is better too.

So what do you think? Does the announcement of no expiration date on miles make the program worth another look? And do you think other airlines will follow suit?